How to avoid CARD CLASH?

New technologies make our life easier however in some circumstances we can hate them. Such situation exists since contactless credit cards has been introduced on the market and has been accepted to be used to pay for bus and tube journey.

Contactless debit or credit card can be recognized by this sign.

Both Oyster card and all contactless debit or credit cards (e.g. PayPass, Wave, Blink) use same technology which is called RFID (Radio Frequency IDentification). Briefly saying this technology uses electromagnetic waves to communicate wirelessly with the reader. One of advantages of such feature is that you can quickly get into bus or tube station, pay for coffee or other small things but besides benefits there are also disadvantages such as called by TFL (Transport of London) "CARD CLASH".

Because both type of cards operates on same frequency 13,56 MHz we can meet with card conflict (CARD CLASH) whilst reading them by the reader. This may happen when we keep both cards close to each other in regular wallet and try to get into bus or tube by touching entire wallet to the reader.

In such scenario two things can happen:

- Reader start blinking with red light which means CARD CLASH and no entry (gate does not open)

- Reader will read one of "visible" cards. Which one? This is random and your fare for a journey could be charged to a card that you didn't intend to pay with. In worst case you can be charged two maximum fares. This could happen because the yellow card reader reads one card when you touch in at the start of your journey and a different card at the end when you touch out.

On TFL website we can read about tips how to avoid CARD CLASH, wrong or double charging:

- Don't touch a wallet or purse with multiple cards on the yellow card reader

- Keep your Oyster card separate from your contactless payment cards

- Only touch the card you want to use on the reader when touching in and out

Above tips are good but convenient?

- you need to always remember where are your cards (together or separately)

- take out needed card from wallet or carry two wallets (absurd)

Do we really need to bother with such trifles? Is there any way to avoid CARD CLASH? Yes there is solution which we show you below.

RFID cards are placed separately on both different wallet sides.

First of all you need to remember on which side which card is placed and second you never know which card will be read. It leads to CARD CLASH issue or double fare for a journey.

Oyster card and contactless debit card kept on the same wallet side close to each other.